1. Field of the Invention
The present invention relates to a data record medium, a data recording method, a data recording apparatus, an accessing method, and an accessing apparatus applied to for example optical discs.
2. Description of the Related Art
The standard for compact discs (CD), which are common nowadays, is called compact disc audio (CD-DA) and based on standard book (referred to as Red Book). Based on the standard book, various formats have been standardized as so-called CD family. As an extended format of CD, the applicant of the present invention has proposed a data record medium having two record areas. The proposed data record medium has an inner record area (referred to as first area) and an outer record area (referred to as second area). The first area has compatibility with CD. However, the second area does not have it. In the second area, audio data that has been compressed and encrypted is recorded. In addition, the record density of the first area is the same as that of conventional CD (namely, single density). On the other hand, the record density of the second area is twice as high as that of conventional CD (namely, double density).
As an example of the method for accomplishing the double density, the tack pitch is narrowed and/or the linear velocity is decreased. Since the record density of the first area is different from that of the second area, the addressing system for the first area is different from that for the second area. In other words, in the first area, the same addressing system as CD is used. On the other hand, in the second area, a different addressing system from CD is used. To accomplish the double density, the record data amount is increased in comparison with the single density. In the addressing system for CD, information assigned as addresses may become insufficient.
When different types of addresses are recoded, since their types differ from each other, addresses are managed independently in each area. In each area, addresses are zero-reset. When two areas are successively accessed, since the addresses thereof cannot be globally handled, for example, the accessing process becomes complicated as an adverse problem.
Since the track pitch and/or linear velocity of the first record area are different from those of the second record area, when a master disc is created by a mastering device, it takes a long time to switch those parameters. Thus, it is difficult to successively record data in the two record areas. As a result, a non-record area (gap) takes place between the two record areas. When such a non-record portion takes place, a problem of how to record addresses results in. As one method for solving such a problem, addresses may be successively assigned to the first record area and the second record area. In such a case, when the two record areas are successively accessed through the non-record portion, a problem occurs. In other words, the traveling amount of the pickup that accesses the first record area or the second record area differs from that of the pickup that successively accesses the first record area and the second record area in the address change amount (difference).
As another method, addresses are zero-reset and assigned to the first record area and the second record area. In this case, the same address is redundantly assigned to the two record areas. Thus, when the first record area and the second record area are successively accessed, a problem takes place. In addition, when the first record area and the second record area are accessed, the traveling amount in the radius direction of the disc is detected by counting the number of tracks that the pickup traverses using a track traverse signal. However, in a non-record portion, since there is no track, when the pickup traverses the non-record portion, the traveling amount in the radius direction cannot be accurately detected.
Therefore, an object of the present invention is to provide a data record medium, a data recording method, a data recording apparatus, an accessing method, and an accessing apparatus that allow a problem of which two areas cannot be successively accessed due to different types of addresses and the presence of a non-record portion to be solved.
To solve the above-described problem, a first aspect of the present invention is a data record medium having a plurality of record areas in which data is recorded, comprising a first record area for recording addresses in a first addressing system, and a second record area for recording addresses in a second addressing system that is different from the first addressing system, wherein when one of the first addressing system and the second addressing system is converted into the other addressing system, addresses are assigned non-redundantly in said first record area and said second record area.
A second aspect of the present invention is a data recording method for recoding data on a data record medium whose record area is divided into at least a first record area and a second record area, comprising the steps of recording first data to the first record area in a first addressing system, and recording second data to the second record area in a second addressing system, wherein when one of the first addressing system and the second addressing system is converted into the other addressing system, addresses are recorded non-redundantly in the first record area and the second record area.
A third aspect of the present invention is a data recording apparatus for recoding data on a data record medium whose record area is divided into at least a first record area and a second record area, comprising a recording means for recording first data to the first record area in a first addressing system and for recording second data to the second record area in a second addressing system, and a controlling means for causing addresses to be recorded non-redundantly in the first record area and the second record area when one of the first addressing system and the second addressing system is converted into the other addressing system.
A fourth aspect of the present invention is an accessing method for accessing a data record medium divided into at least a first record area and a second record area, addresses being recorded to the first record area in a first addressing system, addresses being recorded to the second record area in a second addressing system that is different from the first addressing system, when one of the first addressing system and the second addressing system is converted into the other addressing system, addresses being assigned non-redundantly in the first record area and the second record area, comprising the steps of reproducing an address of the data record medium, converting the reproduced address into one of the first addressing system and the second addressing system, and accessing a desired position corresponding to the converted address.
A fifth aspect of the present invention is an accessing apparatus for accessing a data record medium divided into at least a first record area and a second record area, addresses being recorded to the first record area in a first addressing system, addresses being recorded to the second record area in a second addressing system that is different from the first addressing system, when one of the first addressing system and the second addressing system is converted into the other addressing system, addresses being assigned non-redundantly in the first record area and the second record area, comprising a reproducing means for reproducing an address of the data record medium, and a controlling means for converting the reproduced address into one of the first addressing system and the second addressing system and accessing a desired position corresponding to the converted address.
According to the present invention, even if the addressing system for a first record area is different from that for a second record area, those addressing systems can be globally handled. As a result, the two record areas can be successively accessed without a problem. In addition, even if there is a non-record portion, the two record areas can be successively accessed without a problem.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof, as illustrated in the accompanying drawings.